Image sensor

ABSTRACT

An image sensor includes a color filter array and a light receiving element. The color filter array includes plural repeating unit cells including first, second, and third unit cells. The first and second unit cells are adjacent to each other in a first direction, the second and third unit cells are adjacent to each other in a second direction transverse to the first direction. Each of the first, second, and third unit cells includes at least one first yellow filter configured to transmit a green component and a red component of incident light, and each of the first, second, and third unit cells does not comprise a red filter configured to transmit the red component of the incident light. The light receiving element is configured to convert the incident light transmitted by the color filter array into electric signals.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a continuation of U.S. application Ser. No.15/596,085, filed on May 16, 2017, now U.S. Pat. No. 10,347,675, issuedJul. 9, 2019, which claims priority of U.S. Provisional Application Ser.No. 62/475,311, filed Mar. 23, 2017, the entirety of which isincorporated by reference herein in their entireties.

BACKGROUND

The present disclosure relates to image sensors.

Image sensors are commonly used in electronic devices such as cellulartelephones, cameras, and computers to capture images. In somearrangements, an electronic device is provided with an array of imagepixels arranged in pixel rows and pixel columns. Circuitry is commonlycoupled to pixel columns for reading out image signals from the imagepixels. Imaging systems employ an image sensor in which the visiblelight spectrum is sampled by red, green, and blue (RGB) image pixelsarranged in a mosaic pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A is a schematic top view of an array of image sensor pixels of animage sensor according to some embodiments of the present disclosure.

FIG. 1B is a schematic cross-sectional view taken along line 1B-1B ofFIG. 1A.

FIG. 2 is a flow chart of an image processing method according to someembodiments of the present disclosure.

FIG. 3 shows a simulation result of spectral response of plural imagesensor pixels of image sensors according to some embodiments of thepresent disclosure.

FIG. 4 is a schematic top view of an image sensor according to someembodiments of the present disclosure.

FIG. 5 is a schematic top view of an image sensor according to someembodiments of the present disclosure.

FIG. 6 is a schematic top view of an image sensor according to someembodiments of the present disclosure.

FIG. 7 is a schematic top view of an image sensor according to someembodiments of the present disclosure.

FIG. 8A is a schematic top view of an image sensor according to someembodiments of the present disclosure.

FIG. 8B is a schematic cross-sectional view taken along line 8B-8B ofFIG. 8A.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

FIG. 1A is a schematic top view of an array of image sensor pixels of animage sensor 100 according to some embodiments of the presentdisclosure. FIG. 1B is a schematic cross-sectional view taken along line1B-1B of FIG. 1A. The image sensor 100 includes a semiconductorsubstrate 112, a color filter array 114, and a lens array 116, andthereby forms an array of image sensing pixels. The semiconductorsubstrate 112 includes a light receiving element configured to convertincident light collected by the lens array 116 and transmitted by thecolor filter array 114 into electric signals. The color filter array 114may be a mosaic pattern including plural repeating unit cells RC. In thepresent embodiments, the unit cell RC includes two-by-two filters,including color filters 114Y, 114G, 114B. Herein, the color filter 114Yis a yellow color filter, the color filter 114G is a green color filter,and the color filter 114B is a blue color filter. The unit cell RC doesnot include a red filter.

Herein, the light receiving element of the semiconductor substrate 112may be an array of photosensitive elements 112Y, 112G, 112B, and thelens array 116 includes arrayed micro lenses 116Y, 116G, 116B. The colorfilters 114Y, 114G, 114B of the color filter array 114, and the microlenses 116Y, 116G, 116B are disposed corresponding to the photosensitiveelements 112Y, 112G, 112B respectively. In some embodiments of thepresent disclosure, the semiconductor substrate 112 has a front side112F and a backside 112S for receiving light, and the color filter array114 is disposed between the backside 112S of the semiconductor substrate112 and the lens array 116, such that light incident into the imagesensor 100 may be collected by the lens array 116, filtered by the colorfilter array 114, and then transmitted to the photosensitive elements112Y, 112G, 112B.

Through the configuration, the photosensitive elements 112Y, 112G, 112B,the color filter array 114, and the lens array 116 form an array ofimage sensing pixels including image sensing pixels 110Y, 110G, and110B. For example, at least one of the image sensing pixels 110Yincludes the photosensitive element 112Y, the color filter 114Y, and themicro lens 116Y, at least one of the image sensing pixels 110G includesthe photosensitive element 112G, the color filter 114G, and the microlens 116G, and at least one of the third image sensing pixels 110Bincludes the photosensitive element 112B, the color filter 114B, and themicro lens 116B. Through the configuration, light incident into theimage sensing pixels 110Y, 110G, and 110B may be respectively collectedby the micro lenses 116Y, 116G, and 116B, respectively filtered by thecolor filters 114Y, 114G, and 114B, and then respectively transmitted tothe photosensitive elements 112Y, 112G, 112B. Herein, depending on thecolor filters 114Y, 114G, 114B, the image sensing pixels 110Y aresensitive to yellow light, the image sensing pixels 110G are sensitiveto green light, and the image sensing pixels 110B are sensitive to bluelight. Accordingly, the image sensor 100 detects light in blue, green,and yellow channels.

In some embodiments of the present disclosure, the yellow light isconsidered as a combination of red light and green light, and the imagesensing pixels 110Y are sensitive to both the red light and green light.In some embodiments of the present disclosure, the array of imagesensing pixels does not include an image sensing pixel only sensitive tored light.

In some embodiments, the photosensitive elements 112Y, 112G, 112B may bephotodiodes. Herein, the photosensitive elements 112Y, 112G, 112B may beformed in the semiconductor substrate 112 by implantation. For example,N+ implants, array-N-well implants, and deep-array-N-well implants maybe performed. In some embodiments, the photosensitive elements 112Y,112G, 112B may be complementary metal oxide-semiconductor (CMOS)sensors. Furthermore, the image sensor 100 may be backside illuminated(BSI) complementary metal-oxide semiconductor image sensor (CIS).

The semiconductor substrate 112 is made of a semiconductor material,such as silicon. In some embodiments, the semiconductor substrate 112may be a silicon substrate doped with P-type dopants such as boron, inwhich case the semiconductor substrate 112 is a P-type substrate.Alternatively, the semiconductor substrate 112 may be another suitablesemiconductor material. For example, the semiconductor substrate 112 maybe a silicon substrate that is doped with N-type dopants such asphosphorous, arsenic, or antimony, in which case the semiconductorsubstrate 112 is an N-type substrate. The semiconductor substrate 112may include other elementary semiconductors such as germanium anddiamond. The semiconductor substrate 112 may optionally include acompound semiconductor and/or an alloy semiconductor. Furthermore, thesemiconductor substrate 112 may include an epitaxial layer (epi layer),may be strained for performance enhancement, and may include asilicon-on-insulator (SOI) structure.

In some embodiments of the present disclosure, the image sensor 100 mayfurther include a passivation layer PL disposed on the backside 112S ofthe semiconductor substrate 112. The passivation layer PL may protectthe semiconductor substrate 112 and provide a planar surface, such thatthe color filter array 114 may be formed on the planar surface of thepassivation layer PL.

In some embodiments of the present disclosure, the color filter 114Ytransmits light in a wavelength of about 480 to about 630 nanometers,but blocks some or all visible light out of the wavelength range. Also,the color filter 114G transmits light in a wavelength of about 480 toabout 580 nanometers, but blocks some or all visible light out of thewavelength range. Also, the color filter 114B transmits light in awavelength of about 430 to about 480 nanometers, but blocks some or allvisible light out of the wavelength range. In some embodiments of thepresent disclosure, a transmittance of the color filters greater thanabout 70% may be considered as “transmit”, while a transmittance of thecolor filters less than about 30 may be considered as “block”. It isnoted that the numerical value should not limit the scope of the presentdisclosure, and the wavelength ranges of the red, green, and blue lighttransmitted by the color filter array 114 may be adjusted and chosenupon circumstances.

Herein, for a light incident on the color filter array 114, the colorfilters 114Y, 114G, and 114B respectively transmit parts of the light.To be specific, the color filter 114Y transmits a red component and agreen component of the incident light, but blocking some or all theother component of the incident light (i.e., the blue component). Thecolor filter 114G transmits the green component of the incident light,but blocking some or the other component of the incident light (i.e.,the red component and the blue component). The color filter 114Btransmits a blue component of the incident light, but blocking some orall the other component of the incident light (i.e., the red componentand the green component).

In some embodiments of the present disclosure, the photosensitiveelements 112Y, 112G, 112B have substantially the same sizes and are madeof the same material, and the photosensitive elements 112Y, 112G, 112Bmay have the same spectral response (or quantum efficiency (QE)). Thecolor filters 114Y, 114G, 114B may be arranged according to theconfiguration of the photosensitive elements 112Y, 112G, 112B, and sizesof the color filters 114Y, 114G, 114B are substantially the same. Inother embodiments, sizes of the photosensitive elements 112Y, 112G, 112Bmay be different from each other, and sizes of the color filters 114Y,114G, 114B may be different from each other.

In some embodiments, the micro lenses 116Y, 116G, 116B may be arrangedaccording to the configuration of the photosensitive elements 112Y,112G, 112B, and the micro lenses 116Y, 116G, 116B may have substantiallythe same structures. In other embodiments, the micro lenses 116Y, 116G,116B may have different structures from each other. In some embodiments,the micro lenses 116Y, 116G, 116B are convex lenses. In someembodiments, each micro lenses 116Y, 116G, 116B has a plano-convexshape.

In some embodiments of the present disclosure, the image sensor 100 mayfurther include an interconnect structure 120 disposed at the front side112F of semiconductor substrate 112 and a processing circuitry 130. Theimage sensing pixels 110Y, 110G, and 110B are electrically connectedwith the processing circuitry 130 through the interconnect structure120. The interconnection structure 120 may include a number of patterneddielectric layers and conductive layers that couple to various dopedfeatures, circuitry, and input/output of the photosensitive elements112Y, 112G, 112B. The interconnection structure 120 includes aninterlayer dielectric (ILD) and a multilayer interconnection (MLI)structure. The MLI structure includes contacts, vias and metal lines.For the purpose of illustration, a number of conductive lines 122 andvias/contacts 124 are shown in FIG. 1B. It being understood that theconductive lines 122 and vias/contacts 124 are exemplary. The actualpositioning and configuration of the conductive lines 122 andvias/contacts 124 may vary depending on design needs and manufacturingconcerns. Through the configuration, electric signals converted from theincident light by the photosensitive elements 112Y, 112G, 112B can beconveyed to the processing circuitry 130 by the interconnect structure120.

In some embodiments, because of the properties of the photosensitiveelements 112Y, 112G, 112B and the color filters 114Y, 114G, and 114B,the spectral sensitivity functions (or spectral responsivity) of the 3color channels in the image sensor 100 may not match those of thedesired output color space (e.g. CIE-XYZ, sRGB, National TelevisionSystem Committee (NTSC)). Thus, color correction is performed totransform the raw color images into the desired color space through acolor correction circuit in the processing circuitry 130. Colorcorrection may be implemented with the following 3×3 color correctionmatrix (CCM) multiplication in Equation (1):

$\begin{matrix}{\begin{bmatrix}A^{\prime} \\B^{\prime} \\C^{\prime}\end{bmatrix} = {\begin{bmatrix}D_{A} & {\alpha \;} & \beta \\\gamma & D_{B} & \delta \\ɛ & \phi & D_{C}\end{bmatrix}\begin{bmatrix}A \\B \\C\end{bmatrix}}} & {{Equation}\mspace{14mu} (1)}\end{matrix}$

Herein, A, B, and C represents the electric signals detected by imagesensors in their color channels, and A′, B′, and C′ are color-correctedred, green, and blue signals in the output color space. The elementsD_(A), D_(B), D_(C), α, β, γ, δ, ε, and φ of the CCM depend on thespectral response of the photosensitive elements and the color filters.There are a variety of methods to obtain the elements of the CCM. Forexample, one method to obtain the elements of the CCM is to optimize thematrix based on the detected yellow, green, and blue electric signals(i.e. A, B, and C in Equation (1)) to minimize the color error in thecolor-corrected red, green, and blue. The color error may be thedifference between the ideal and color-corrected red, green, and bluedata, in which the ideal red, green, and blue data are related to theresponse of human eye to color. For example, the optimization may beperformed by solving the least-squares problem that minimizes thesum-of-squared-difference between the ideal and color-corrected spectralsensitivity function.

In some embodiments, when color correction is applied, noise also goesthrough the matrix multiplication and the noise variance (Δ Y) ischanged. For example, for a silicon-based image sensor, the noisevariance (Δ Y) obtained by optimized the color correction matrix may bedenoted as follows:

ΔY ²=(0.299D _(A)+0.587γ+0.114ε)² ΔA ²+(0.299α+0.587D _(B)+0.114φ)² ΔB²+(0.299β+0.587δ+0.114D _(C))² ΔC ²  Equation (2)

In some circumstances, although the 3×3 CCM multiplications minimizesthe color error in the color-corrected red, green, and blue data, the3×3 CCM multiplication can amplify the noise variance (Δ Y). Forexample, in a RGB detecting system, A, B, and C are associated with red,green, and blue electric signals respectively, which are detected byimage sensing pixels having red, green, and blue color filtersrespectively. The detected red, green, and blue electric signals aretransformed into color-corrected red, green, and blue data by its CCM.However, when color correction is applied, the values of the elementsD_(A), D_(B), and D_(C) of the CCM in the RGB detecting system are quiteapart, and therefore the noise variance (Δ Y) is large.

In some embodiments of the present disclosure, for reducing the noisevariance (Δ Y), a YGB detecting system is used. FIG. 2 is a flow chartof an image processing method 200 according to some embodiments of thepresent disclosure. Reference is made to FIG. 1A and FIG. 2. At step210, the image sensor 100 may receive a light and convert the light intoat least yellow, green, and blue electric signals by the image sensor100. In some embodiments, the light may be a visible light coming froman object or an image and impinging on the image sensing pixels 110Y,110G, and 110B. As illustrated above, the image sensing pixels 110Y,110G, and 110B are sensitive to yellow, green, and blue lightrespectively. Therefore, a green component and a red component of thelight is converted into the yellow electric signal by the image sensingpixel 110Y, the green component of the light is converted into the greenelectric signal by the image sensing pixel 110G, and a blue component ofthe light is converted into the blue electric signal by the imagesensing pixel 110B. Herein, the yellow, green, and blue electric signalsare associated with A, B, and C respectively in Equation (1).

At step 220, information associated the yellow, green, and blue electricsignals are processed, so as to obtain a CCM herein. As mentioned above,the CCM is a result of optimization. For example, the CCM may beobtained by solve the least-squares problem that minimizes thesum-of-squared-difference between the ideal and color-corrected spectralsensitivity function.

At step 230, a set of a red image data, a green image data, and a blueimage data are determined based on the information associated with theyellow, green, and blue electric signals. For example, the yellow,green, and blue electric signals may be multiplexed by the colorcorrection matrix, so as to obtain color-corrected red, green, and bluedata. Thus, the detected yellow, green, and blue electric signals (i.e.A, B, and C in Equation (1)) are transformed to color-corrected red,green, and blue data (i.e. A′, B′, and C′ in Equation (1)) by its CCM.The CCM of the YGB detecting system is different from the CCM of the RGBdetecting system. Through the configuration, the values of the elementsD_(A), D_(B), and D_(C) of the CCM of the YGB detecting system areclose, and therefore the noise variance (Δ Y) is small.

FIG. 3 shows a simulation result of spectral response of plural imagesensing pixels of image sensors according to some embodiments of thepresent disclosure. The dash-dotted lines R1, G1, and B1, indicate thespectral response of the image sensing pixels having the red, green, andblue color filter respectively in the RGB detecting system, while thesolid line Y2, and the dashed lines G2, and B2, indicate the spectralresponses of the image sensing pixels 110Y, 110G, and 110B of the imagesensor 100 in the YGB detecting system. The image sensing pixels 110Yhaving the yellow color filter has a spectral response covers that ofthe image sensing pixel having the red color filter and the imagesensing pixel having the green color filter (i.e., the solid line Y2covers the dash-dotted lines R1 and G1), and thus the first imagesensing pixels 110Y produces signals (which may be the value A) inresponse to red light and green light. In some embodiments, the imagesensing pixels 110Y have greater spectral response (or quantumefficiency) than that of the image sensing pixel having the red colorfilter (i.e., QE of the solid line Y2 is greater than QE of thedash-dotted line R1). For example, the spectral response at thewavelength of 560 to 600 nanometers of the image sensing pixels 110Y isgreater than that of the image sensing pixel having the red colorfilter. In some embodiments, the image sensing pixels 110Y have greaterspectral response (or quantum efficiency) than that of the image sensingpixel having the green color filter or the image sensing pixels 110G.For example, a transmittance of the color filter 114Y of the imagesensing pixels 110Y transmit the green light (e.g., light in awavelength of about 480 to about 580 nanometers) is greater than atransmittance of the color filter 114G of the image sensing pixels 110Gtransmit the green light (i.e., QE of the solid line Y2 is greater thanQE of the dash line G2). Therefore, in the YGB detecting system, theintensity of the detected signals (which may be the value A) isenhanced.

Reference is made to FIG. 1A. In present embodiments, the color filterarray 114 does not include a red color filter, which transmits redlight, but blocks some or all blue light and green light, such that thearray of image sensors does not include an image sensing pixel onlysensitive to red light. Through the configuration, the signals producedby the image sensor 100 are processed by the CCM in the YGB detectingsystem, instead of being processed by the CCM in the RGB detectingsystem. Therefore, the noise variance is small and the intensity of thesignals is enhanced.

In some embodiments of the present disclosure, the number of the imagesensing pixels 110G is twice the number of the image sensing pixels 110Yor the number of the image sensing pixels 110B, so as to mimic thephysiology of the human eye. Herein, the unit cell RC includes atwo-by-two color filters, such that the mosaic pattern includes atwo-by-two image sensing pixels, with two image sensing pixels 110Gdiagonally opposite one another, along with the image sensing pixels110Y and the image sensing pixels 110B that are diagonally opposite oneanother. However, it should not limit the scope of the presentdisclosure. In some other embodiments, the image sensing pixels may beconfigured with various kinds of mosaic patterns according toapplication requirements.

FIG. 4 is a schematic top view of an image sensor 100 according to someembodiments of the present disclosure. The present embodiments aresimilar to the embodiments of FIG. 1A and FIG. 1B, and the differencebetween the present embodiments and the embodiments of FIG. 1A and FIG.1B is that the image sensor 100 further includes image sensing pixels110W. Herein, the image sensing pixels 110W may not include a visiblecolor filter, such that the image sensing pixels 110W are sensitive tolights depending on the property of the photosensitive elements. Thatis, the image sensing pixels 110W are clear, or otherwise known aspanchromatic pixels. In some embodiments, the image sensing pixel 110Wmay also include the photosensitive elements and the micro lenses, asstructure of the image sensing pixels 110Y, 110G, and 110B.

In the present embodiments, the number of the image sensing pixels 110Wis greater than a sum of the number of the image sensing pixels 110Y,110G, and 110B, and the image sensing pixels 110Y, 110G, and 110B aredistributed in an approximate triangular array, with most pixelsunfiltered. However, it should not limit the scope of the presentdisclosure. In some other embodiments, the number of the image sensingpixels 110W may be smaller than a sum of the number of the image sensingpixels 110Y, 110G, and 110B. Other details of the present embodimentsare substantially the same as the embodiments of FIG. 1A and FIG. 1B,and not repeated herein.

FIG. 5 is a schematic top view of an image sensor 100 according to someembodiments of the present disclosure. The present embodiments aresimilar to the embodiments of FIG. 1A and FIG. 1B, and the differencebetween the present embodiments and the embodiments of FIG. 1A and FIG.1B is that the image sensor 100 further includes image sensing pixels110MIR, 110NIR, 110NUV, and 110MUV. The image sensing pixels 110MIR,110NIR, 110NUV, and 110MUV are respectively sensitive to medium infraredred light, near infrared red light, near ultra-violet light, and mediumultra-violet light. Through the configuration, the image sensor 100 maydetects seven colors, and may be useful in astronomy.

The image sensing pixels 110MIR, 110NIR, 110NUV, and 110MUV may includecolor filters 114MIR, 114NIR, 114NUV, and 114MUV. The color filters114MIR, 114NIR, 114NUV, and 114MUV may transmit the medium infrared redlight, the near infrared red light, the near ultra-violet light, and themedium ultra-violet light, but block the red, green, and blue light,which can be transmitted by the color filters 114Y, 114G, 114B. In someembodiments, the image sensing pixels 110MIR, 110NIR, 110NUV, and 110MUValso include the photosensitive elements and the micro lenses, asstructure of the image sensing pixels 110Y, 110G, and 110B. Otherdetails of the present embodiments are substantially the same as theembodiments of FIG. 1A and FIG. 1B, and not repeated herein.

FIG. 6 is a schematic top view of an image sensor 100 according to someembodiments of the present disclosure. The present embodiments aresimilar to the embodiments of FIG. 1A and FIG. 1B, and the differencebetween the present embodiments and the embodiments of FIG. 1A and FIG.1B is that the image sensor 100 includes image sensing pixels 110Y ofdifferent sizes, image sensing pixels 110G of different sizes, and imagesensing pixels 110B of different sizes.

In the present embodiments, the image sensing pixels 110Y have twosizes, the image sensing pixels 110G have two sizes, and the imagesensing pixels 110B have two sizes. In the present embodiments, thelarge sensor pixels are octagonal, and smaller square pixels are placedin the square areas between the large sensor pixels. Through theconfiguration, if an image is slightly overexposed, so that the largersensor pixels are saturated, an image with proper contrast can beobtained from the smaller pixels.

In the present embodiments, a portion of the image sensing pixels 110Gare arranged in one column, and a portion of the image sensing pixels110Y and 110B are interlaced in another column. Through theconfiguration, as illustrated previously, the number of the imagesensing pixels 110G is twice the number of the image sensing pixels 110Yor the number of the image sensing pixels 110B, so as to mimic thephysiology of the human eye.

Other details of the present embodiments are substantially the same asthe embodiments of FIG. 1A and FIG. 1B, and not repeated herein.

FIG. 7 is a schematic top view of an image sensor 100 according to someembodiments of the present disclosure. The present embodiments aresimilar to the embodiments of FIG. 1A and FIG. 1B, and the differencebetween the present embodiments and the embodiments of FIG. 1A and FIG.1B is at least that the image sensor 100 further includes image sensingpixels 110W, 110C, and 110E. In the present embodiments, the imagesensing pixels 110W may not include a color filter, such that the imagesensing pixels 110W are sensitive to lights depending on the property ofthe photosensitive elements. That is, the image sensing pixels 110W areclear, or otherwise known as panchromatic pixels. In the presentembodiments, the image sensing pixels 110C may include cyan colorfilters 114C, and the image sensing pixels 110E may include yellow colorfilters 114E. The color filters 114C and 114E transmit cyan and yellowlight respectively. In some embodiments, the image sensing pixels 110W,110C, and 110E may also include the photosensitive elements and themicro lenses, as structure of the image sensing pixels 110Y, 110G, and110B.

In some embodiments of the present embodiments, the yellow color filters114E of the image sensing pixels 110E and the yellow color filters 114Yof the image sensing pixels 110Y may be made of the same materials. Thatis, for a unit cell RC, the yellow color filters 114E of the imagesensing pixels 110E and the yellow color filters 114Y of the imagesensing pixels 110Y may have substantially the same transmittancespectrum.

The sizes of the image sensing pixels 110W, 110C, and 110E are differentfrom the sizes of the image sensing pixels 110Y, 110G, and 110B. Herein,the sizes of the image sensing pixels 110Y, 110G, and 110B are smallerthan the sizes of the image sensing pixels 110W, 110C, and 110E. To bespecific, the large image sensing pixels 110W, 110C, and 110E wereoctagonal, and smaller square image sensing pixels 110Y, 110G, and 110Bwere placed in the square areas between the large sensor pixels. Throughthe configuration, if an image is slightly overexposed, so that thelarger sensor pixels are saturated, an image with proper contrast can beobtained from the smaller pixels. Furthermore, the difference in sizescould be augmented by the use of a yellow/cyan/unfiltered array for thelarge pixels, that lets in more light, and a yellow/blue/green array,letting in less light for the small pixels.

In the present embodiments, the lens array 116 (see FIG. 1B) includesplural octagonal micro lenses corresponding to the image sensing pixels110W, 110C, and 110E, while leaving the image sensing pixels 110Y, 110G,and 110B without micro lenses.

Other details of the present embodiments are substantially the same asthe embodiments of FIG. 1A, FIG. 1B, and FIG. 5, and not repeatedherein.

FIG. 8A is a schematic top view of an image sensor 100 according to someembodiments of the present disclosure. FIG. 8B is a schematiccross-sectional view taken along line 8B-8B of FIG. 8A. The presentembodiments are similar to the embodiments of FIG. 1A and FIG. 1B, andthe difference between the present embodiments and the embodiments ofFIG. 1A and FIG. 1B is at least that a first portion of the color filterarray 114 includes repeating unit cells RC, and a second portion of thecolor filter array 114 includes another repeating unit cells RC′.

In the present embodiments, the unit cell RC′ may include color filters114R, 114G, and 114B, while the unit cell RC includes the color filters114Y, 114G, and 114B. The red color filter 114R transmits red light, butblocking some or all blue and green light. Therefore, image sensingpixels 110R including the color filter 114R is sensitive to red light.In some embodiments, the image sensing pixel 110R may also include aphotosensitive element 112R and a micro lens 116R, as the structure ofthe image sensing pixels 110B and 110G.

Herein, the unit cells RC and the unit cells RC′ have the same pattern,and the color filters 114Y of the unit cell RC is at a first location ofthe pattern, and the color filters 114R of the unit cell RC′ is also ata first location of the pattern. In some embodiments, the color filters114G of the unit cell RC and the color filters 114G of the unit cell RC′are both at a second location of the pattern. In some embodiments, thecolor filters 114B of the unit cell RC and the color filters 114B of theunit cell RC′ are both at a second location of the pattern. The colorfilters 114G and 114B of the unit cell RC′ may be substantially the sameas that of the color filters 114G and 114B of the unit cell RC.

In the present embodiments, the image sensor 100 is implemented withboth the YGB and the RGB detecting systems. Herein, the first portion ofthe color filter array 114 including the unit cells RC is associatedwith the YGB detecting systems, while the second portion of the colorfilter array 114 including the unit cells RC′ is associated with the RGBdetecting systems. Through the configuration, when light is incidentonto the color filter array 114, a first portion of the light isconverted into the yellow, green, and blue electric signals by the imagesensing pixels 110Y, 110G, and 110G within the unit cells RC, while asecond portion of the light is converted into the red, green, and blueelectric signals by the image sensing pixels 110R, 110G, and 110G withinthe unit cells RC′. To be specific, yellow (i.e., a combination of redand green), green, blue components of the first portion of the light areconverted into the yellow, green, and blue electric signalsrespectively, while red, green, blue components of the second portion ofthe light are converted into the red, green, and blue electric signalsrespectively.

The information associated with the yellow, green, and blue electricsignals detected by the image sensing pixels 110Y, 110G, and 110G withinthe unit cells RC is processed to obtain a first color correctionmatrix, and the information associated with the red, green, and blueelectric signals detected by the image sensing pixels 110R, 110G, and110G within the unit cells RC′ is processed to obtain a second colorcorrection matrix. A first set of a red image data, a green image data,and a blue image data are determined based on the information associatedwith the yellow, green, and blue electric signals detected by the imagesensing pixels 110Y, 110G, and 110G within the unit cells RC, while asecond set of a red image data, a green image data, and a blue imagedata are determined based on the information associated with the red,green, and blue electric signals detected by the image sensing pixels110R, 110G, and 110G within the unit cells RC′. Through theconfiguration, some of the signals produced by the image sensor 100 areprocessed by the CCM in the YGB detecting system, while some of thesignals produced by the image sensor 100 are processed by the CCM in theRGB detecting system.

Other details of the present embodiments are substantially the same asthe embodiments of FIG. 1A and FIG. 1B, and not repeated herein.

In some embodiments of the present disclosure, the image sensor 100detects light in the yellow, green, and blue color channels, so that thespectrum response of the image sensor 100 is enhanced and when the rawcolor images is transformed into the desired color space through a colorcorrection, the noise variance (ΔY) is reduced.

According to some embodiments of the present disclosure, the imagesensor includes a color filter array and a light receiving element. Thecolor filter array includes plural repeating unit cells, the repeatingunit cells including first, second, and third unit cells. The first andsecond unit cells are adjacent to each other in a first direction, thesecond and third unit cells are adjacent to each other in a seconddirection transverse to the first direction. Each of the first, second,and third unit cells includes at least one first yellow filterconfigured to transmit a green component and a red component of incidentlight, and each of the first, second, and third unit cells does notcomprise a red filter configured to transmit the red component of theincident light. The light receiving element is configured to convert theincident light transmitted by the color filter array into electricsignals.

According to some embodiments of the present disclosure, an image sensorincludes a color filter array and a light receiving element. The colorfilter array includes plural repeating unit cells, the repeating unitcells including first, second, and third unit cells. The first andsecond unit cells are adjacent to each other in a first direction, thesecond and third unit cells are adjacent to each other in a seconddirection transverse to the first direction. Each of the first, second,and third unit cells includes at least one yellow filter and at leastone green filter. The yellow filter is configured to transmit a greencomponent and a red component of incident light, in which the yellowfilter is configured to transmit the green component of the incidentlight with a first transmittance. The green filter is configured totransmit the green component of the incident light with a secondtransmittance, in which the first transmittance is greater than thesecond transmittance. The light receiving element is configured toconvert the incident light transmitted by the color filter array intoelectric signals.

According to some embodiments of the present disclosure, an image sensorincludes a color filter array and a light receiving element. The colorfilter array includes repeating unit cells, the repeating unit cellsincluding first, second, and third unit cells. The first and second unitcells are adjacent to each other in a first direction, the second andthird unit cells are adjacent to each other in a second directiontransverse to the first direction. Each of the first, second, and thirdunit cells includes a first filter, a second filter, and a third filter.The first filter is configured to transmit a first component of incidentlight and block a second component and a third component of the incidentlight. The second filter is configured to transmit the first componentand the second component of the incident light and block the thirdcomponent of the incident light. The third filter is configured totransmit the third component of the incident light and block the firstand second components of the incident light. Each of the first, second,and third unit cells does not include a filter configured to transmitthe second component of the incident light and block the first and thirdcomponents of the incident light. The light receiving element isconfigured to convert the incident light transmitted by the color filterarray into electric signals.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. An image sensor, comprising: a color filterarray, comprising a plurality of repeating unit cells, the plurality ofrepeating unit cells comprising first, second, and third unit cells,wherein the first and second unit cells are adjacent to each other in afirst direction, the second and third unit cells are adjacent to eachother in a second direction transverse to the first direction, and eachof the first, second, and third unit cells comprises at least one firstyellow filter configured to transmit a green component and a redcomponent of incident light, and each of the first, second, and thirdunit cells does not comprise a red filter configured to transmit the redcomponent of the incident light; and a light receiving elementconfigured to convert the incident light transmitted by the color filterarray into electric signals.
 2. The image sensor of claim 1, whereineach of the first, second, and third unit cells further comprises atleast one green filter configured to transmit the green component of theincident light.
 3. The image sensor of claim 2, wherein a size of thefirst yellow filter is equal to a size of the green filter.
 4. The imagesensor of claim 2, wherein the number of a plurality of the greenfilters of one of the first, second, and third unit cells is twice thenumber of the at least one first yellow filter of the one of the first,second, and third unit cells.
 5. The image sensor of claim 2, whereinthe number of the at least one green filter of one of the first, second,and third unit cells is equal to the number of the at least one firstyellow filter of the one of the first, second, and third unit cells. 6.The image sensor of claim 2, wherein the first yellow filter isconfigured to transmit the green component of the incident light with afirst transmittance, the green filter is configured to transmit thegreen component of the incident light with a second transmittance, andthe first transmittance is greater than the second transmittance.
 7. Theimage sensor of claim 1, wherein each of the first, second, and thirdunit cells further comprises at least one blue filter configured totransmit a blue component of the incident light.
 8. The image sensor ofclaim 7, wherein a size of the first yellow filter is equal to a size ofthe blue filter.
 9. The image sensor of claim 1, wherein each of thefirst, second, and third unit cells further comprises at least onesecond yellow filter configured to transmit the green component and thered component of incident light, and a size of the first yellow filteris greater than a size of the second yellow filter.
 10. An image sensor,comprising: a color filter array, comprising a plurality of repeatingunit cells, the plurality of repeating unit cells comprising first,second, and third unit cells, wherein the first and second unit cellsare adjacent to each other in a first direction, the second and thirdunit cells are adjacent to each other in a second direction transverseto the first direction, and each of the first, second, and third unitcells comprises: at least one yellow filter configured to transmit agreen component and a red component of incident light, wherein theyellow filter is configured to transmit the green component of theincident light with a first transmittance; and at least one green filterconfigured to transmit the green component of the incident light with asecond transmittance, wherein the first transmittance is greater thanthe second transmittance; and a light receiving element configured toconvert the incident light transmitted by the color filter array intoelectric signals.
 11. The image sensor of claim 10, wherein a size ofthe yellow filter is equal to a size of the green filter.
 12. The imagesensor of claim 10, wherein the number of the at least one green filterof one of the first, second, and third unit cells is equal to or greaterthan the number of the at least one yellow filter of the one of thefirst, second, and third unit cells.
 13. The image sensor of claim 10,wherein each of the first, second, and third unit cells does notcomprise a red filter configured to transmit the red component of theincident light.
 14. An image sensor, comprising: a color filter array,comprising a plurality of repeating unit cells, the plurality ofrepeating unit cells comprising first, second, and third unit cells,wherein the first and second unit cells are adjacent to each other in afirst direction, the second and third unit cells are adjacent to eachother in a second direction transverse to the first direction, and eachof the first, second, and third unit cells comprises: a first filterconfigured to transmit a first component of incident light and block asecond component and a third component of the incident light; a secondfilter configured to transmit the first component and the secondcomponent of the incident light and block the third component of theincident light; and a third filter configured to transmit the thirdcomponent of the incident light and block the first and secondcomponents of the incident light, wherein each of the first, second, andthird unit cells does not comprise a filter configured to transmit thesecond component of the incident light and block the first and thirdcomponents of the incident light; and a light receiving elementconfigured to convert the incident light transmitted by the color filterarray into electric signals.
 15. The image sensor of claim 14, wherein awavelength of the second component of the incident light is longer thana wavelength of the first component of the incident light and awavelength of the third component of the incident light.
 16. The imagesensor of claim 14, wherein a wavelength of the first component of theincident light is between a wavelength of the second component of theincident light and a wavelength of the third component of the incidentlight.
 17. The image sensor of claim 14, wherein a wavelength of thefirst component of the incident light is in a range from 480 nanometersto 580 nanometers, and a wavelength of the first component of theincident light and the second component of the incident light are in arange from 480 nanometers to 630 nanometers.
 18. The image sensor ofclaim 14, wherein the first filter is configured to transmit the firstcomponent of the incident light with a first transmittance, the secondfilter is configured to transmit the first component of the incidentlight with a second transmittance, and the second transmittance isgreater than the first transmittance.
 19. The image sensor of claim 14,wherein the light receiving element comprises: a first photosensitiveelement configured to convert the first component of the incident lighttransmitted by the first filter into a first electric signal; a secondphotosensitive element configured to convert the first and secondcomponents of the incident light transmitted by the second filter into asecond electric signal; and a third photosensitive element configured toconvert the third component of the incident light transmitted by thethird filter into a third electric signal.
 20. The image sensor of claim19, wherein the light receiving element further comprises a fourthphotosensitive element configured to receive the first to thirdcomponents of the incident light.